$7.$ Which of the following is MOST LIKELY a fixed cost? A$.$ Rent on a retail store that is $$1,000$ per month plus $10\%$ of sales. B$.$ Depreciation on a piece of equipment that is set at $$0\mathrm{.}57$ per unit produced. C$.$ Advertising costing $$10,000$ billed on a one$-$year contract. D$.$ The cost of applying $$10$ in paint to the side of each of four walls in pre$-$manufactured homes.